Subject:Dormice 'take naps to aid chances of survival'

The notoriously sleepy dormouse may be even sleepier than previously thought and researchers say naps help the animals survive until hibernation.

Researchers in Vienna found that when less food was available, garden dormice used a short sleep-like state called torpor to save energy.

The animals also appear to use torpor when the weather is colder.

They presented their findings at the Society for Experimental Biology's annual meeting in Manchester, UK.

Lead researcher Dr Sylvain Giroud from the University of Veterinary Medicine, Vienna compared dormice that had unlimited supplies of food with those that were fasted on alternate days.

The food-restricted dormice used torpor more frequently and entered the sleep-like state for longer than those animals that were able to feed freely.

While they are in this state, their metabolic rate slows and their body temperature is reduced, which saves energy. This allows the animals to store more body fat, which is crucial for their winter survival.

"This shows how the wild mice cope with the unpredictability of food," explained Dr Giroud.

In the same study, the researchers found that animals born later in the year "caught up" with those that were born earlier by growing faster. They believe that these late-born mice use torpor to help maintain this growth rate.

"I think these dormice are quite flexible in the use of torpor," explained Dr Giroud. "So, for example, this might be an advantage to fatten up more quickly if the winter is coming fast."

The researcher added that he hopes to learn more about the garden dormouse ecology in order to aid their conservation, as their numbers are in decline.